Need help with my new Comet...

Syngefinger

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As stated in another thread, I recently picked up a COMET pinball from that a local guy had listed on CL. Before I bought it I noticed that the voices weren't working during gameplay, but the seller told me the voices annoyed his wife, so he had them turned off. I figured it wouldn't be very hard to get them working again. Apparently, I was wrong or I am missing something simple?

When I push the manual test switch on the CPU, the voices cycle through properly and when I push the 2nd test switch on the CPU it gives me a code of "0" which, according to the sticker inside the head, means that no errors were detected. I've tried to adjust both volume knobs, located on the sound board and the one on the inside left of the cabinet. Those both only seem to increase the volume only and no speech is heard, as I've read that the one knob supposedly increases the amount of speech effects. Is this correct?

Also, if the voices are working when the test switch is active, but otherwise not heard in the game, could it possibly be a bad ROM? I've noticed that the U4, U5, U6 and U7 speech roms are all present. If the U-20 Speech rom was bad, would the manul tests switches on the CPU still produce speech? Any pinball experts have any ideas as to what to check next?
 
bad volume pot or connector (IP16/IJ16)? but that wouldn't really be indicated, since the diagnostic speech works fine. unless in that diagnostic it bypasses the volume control.

have you tried the menu-driven speech test (rather than the one triggered from the board itself)?
 
In your game adjustment menu make sure Setting 34 is set to 00 or 04. Setting it to 00 enables all sounds with liberal duck target settings, and 04 enables all sounds with conservative duck target settings.

Hopefully that will get them working...

One more thing, there is a trimmer pot on the sound board. I'm not 100% sure it works like this in Comet but on previous Williams games the trimmer was a balance between sound effects a voice, so put the game into sounds test and play with that pot to make sure you hear sounds and voice.
 
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bad volume pot or connector (IP16/IJ16)? but that wouldn't really be indicated, since the diagnostic speech works fine. unless in that diagnostic it bypasses the volume control.

have you tried the menu-driven speech test (rather than the one triggered from the board itself)?

I have tried the menu-driven speech test and all I get are sound effects, with no speech. The only time I get the speech effects are from the board test switch. I'm not really sure how to check the volume pot or the connector. My repair skills are not very advanced, I'm afraid.

In your game adjustment menu make sure Setting 34 is set to 00 or 04. Setting it to 00 enables all sounds with liberal duck target settings, and 04 enables all sounds with conservative duck target settings.

Hopefully that will get them working...

One more thing, there is a trimmer pot on the sound board. I'm not 100% sure it works like this in Comet but on previous Williams games the trimmer was a balance between sound effects a voice, so put the game into sounds test and play with that pot to make sure you hear sounds and voice.

I have tried Setting 34 to both 00 and 04, and it didn't seem to make any difference. I also tried using the trimmer pot when the sound test was running, hoping to adjust the speech back in with the effects, but couldn't get the voices to come in.

Any thing else that I could check? Might I need to find a replacement sound board? Or possibly try replacing some of the speech ROMS?
 
If you hear voices via the board test then the roms are fine. How comfortable are you doing your own boardwork?

It could be the op-amp at U3. You could try replacing that and see if it brings your voice back.

I do have a speech board for this generation of game that came out of a sorcerer. It's marked good but I have no way to retest it at the moment. I'd sell it for a nominal amount if you exhaust your patience with your current board. You'd just have to swap in your ROM's and plug it in.
 
If you hear voices via the board test then the roms are fine. How comfortable are you doing your own boardwork?

It could be the op-amp at U3. You could try replacing that and see if it brings your voice back.

I do have a speech board for this generation of game that came out of a sorcerer. It's marked good but I have no way to retest it at the moment. I'd sell it for a nominal amount if you exhaust your patience with your current board. You'd just have to swap in your ROM's and plug it in.

Not real comfortable. I do have a friend that might be capable of doing the work, although actually getting him over to help is sometimes difficult. It might be easier (and quicker) to just purchase your board. I'll shoot you a PM, craigmack. Thanks!
 
I received the replacement Speech board from craigmack today. Thanks for such quick shipping! Anyway, I got it installed tonight and it seemed to make no difference at all. No matter what I tried, through different settings, adjustment of the 2 knobs and what not. All I seem to get are the effects noises and no speech whatsoever. When I do the Speech Diagnostic test on the CPU the speech works fine, but once I turn the machine off and then on again, it goes right back to effects noises only.

It seems that even if I change the settings from 00, 01, 02, 03, 04, 05 or 06 in Function 34, that the same sound effects are enabled, even if they are supposed to be set to off. I have found that the knocker has one wire clipped from it and that in function 34 in some functions it uses the knocker. Might that be causing these strange occurances?
 
So if you are able to hear the voices on the voice board, then the problem has to be on the CPU side. There is a PIA 6821 chip that controls the signals from the CPU to the voice board CPU. Pressing the diagnostic switch on the sound board tests the board but does not test the PIA. I would look there next. If it is socketed, then its easy to swap in a new one. If it is not then you will need to desolder the chip, add a socket and pop in a new one.
 
So if you are able to hear the voices on the voice board, then the problem has to be on the CPU side. There is a PIA 6821 chip that controls the signals from the CPU to the voice board CPU. Pressing the diagnostic switch on the sound board tests the board but does not test the PIA. I would look there next. If it is socketed, then its easy to swap in a new one. If it is not then you will need to desolder the chip, add a socket and pop in a new one.

Ok, thanks craigmack. That seems to make perfect sense and quite possibly explain things. I'll check this out tomorrow night when my electronics friend technician is coming over to help me. This gives me some hope.
 
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